Step 30 Use Uhm's law applied to Series Circults to calculate the circult current. v 3 I = g R+R R R, Step 4: Then verify this calculated value by measuring the current with an ammeter, as shown in Figure 5, make sure to change multimeter on Amp mode. When you measure current with a digital meter, the meter may show the appropriate metric prefix symbol (m or p) in some corner of the display. These metric prefixes are easy to overlook when reading the display of a digital meter, so pay close attention